A variety of Wireless Internet Service Providers (ISP) provides hotspots at various locations around the world. A hotspot is a venue that offers Wireless Local Area Network (WLAN) access to a network, such as the Internet. These hotspots can appear as unprotected WLANs. However, these hotspots break the assumption that once a network link comes up on a mobile client with the WLAN and an Internet Protocol (IP) address is acquired by the mobile client, that the mobile client will have Internet connectivity. Instead, these networks redirect hypertext transfer protocol (HTTP) traffic to a capture web page and block some or all other IP traffic until the user has agreed to terms and conditions, authenticate to the network, and/or purchased access. These types of networks are called captive networks. This model requires user intervention every time a user joins the WLAN. For example, WLAN service is free and the user simply has to click on a button in a web page to indicate that the user agrees to the terms of the service before the mobile client is allowed access. Alternatively, the user must provide some sort of credentials (e.g., username and/or password) to access the Internet via the WLAN. Thus, in this model, the user must know to launch a web browser and attempt to load a web page in order to access the Internet through one of these networks.
The act of associating with a WLAN often involves no user interaction. A mobile client can automatically associate with a WLAN network if the mobile client has associated with that WLAN in the past. A mobile client can also support both WLAN and cellular data service, where the cellular data service is also available. Associating such a mobile client with a captive network breaks the seamless networking experience because the mobile client will associate with the captive network without gaining Internet access and drop the cellular data service connection. Applications that handle mail, weather, and stock information, for example, will stop working because the user walked by a venue and this mobile client joined the hotspot corresponding to the venue. It would be useful to automatically negotiate access to a captive network without dropping data connections to other networks.